Communications systems necessarily utilize communication channels. These channels are non ideal, band width limited paths over which information must be communicated or transported. These channels impose limits on the amount of information that may be communicated in a unit time. Such a limit may be referred to as a channel capacity. The channel capacity together with other properties of the channel, such as various forms of noise interference, will, with statistical certainty, cause or otherwise result in the occurrence of errors in the information that is communicated over the channel. These effects may be particularly evident on wireless channels such as those utilized by wireless communications systems, particularly wireless data communications systems. Practitioners in the art have long recognized these phenomenon and have with varying degrees of success developed approaches to deal with the effects of a non ideal channel.
Some of these approaches include forward error correction (FEC) and backward error correction (BEC). FEC includes techniques, such as various forms of encoding or redundancy or duplication of the information as transmitted, directed to assuring that the correct information may be recovered, regardless of whether an error occurred, during or as a result of communication over the channel. In contrast BEC includes techniques, such as Automatic transmission Retry reQuest (ARQ) or various acknowledgment protocols, directed to assuring that correct information is ultimately made available whenever an error has occurred. In any event most all forms of FEC and especially BEC require a portion of the channel capacity and thus detract, at least in theory, from the amount of information that otherwise may be transported over the channel. Clearly a need exists for a method of forward error correction that minimizes the impact on channel capacity.